Quick summary

03 Polaris 500 H.O. Transmission mated with a 800cc two stroke Polaris engine.

Problem: vehicle does 20 mph tops, has no low end pull, or top end pull

- belt does not seem to be slipping
- clutches seem to be operating correctly
- gearing in transaxle seems WAY off- it takes 10 revolutions on the secondary to
produce one tire revolution in High, in low it takes 25. So with the vehicle on jack
stands and the engine screaming at 8k rpms, the tires are rotating very slowly.

For all you Polaris gurus. Can you verify or comment on the gear ratio, that is how many times the secondary should rotate per tire revolution?

Thanks so much!

 

Since the gearing of all those style trannys are the same from at least '99 to '04, I would not think that the tranny input/output ratios you are looking at are your problem - have you mixed/matched the ATV clutch and sled clutch? Or is the Primary clutch possibly slipping on the crankshaft? If they are not tight, they can and will slip on the crank............

 

engine running 8000 rpms clutches working properly would mean that the secondary would be turning faster than the primary. that being said the the rear wheels should be flying. even at a 1 to 1 ratio between the primary and secondary should net you 800 revolutions of the tire in 60 seconds at 8000 rpm at the engine correct?

 

did you change the clutches componets asa well and are you using an 800 sled clutch hopefully. (airwolf) i used to have that name for my cb handle lol.

 

Stock Sled primary and stock ATV secondary. I think the secondary spring rate may be way to light, thus opening all the way right away, thus the belt has no side load resistance to turn the tires. I think my next move will be a heavier secondary spring.

I did anticipate the need for clutch tuning and likely some heavier duty aftermarket clutch parts, but did not count on it being this far off.

Thanks for all the help so far.

 

just a thought, but can you use a sled secondary as well or wont it fit on the shaft and in the outside of the clutch too large for the cover. just wondering. the spring theroy sounds right as there is alot stronger springs in the sleds for the high r's of the sled.

 

Personally I would get a matched set of non ebs atv clutches and the go from there. Then make sure that your belt deflection is correct. Get a tach and then adjust to the engines rpm range. What luck I have some clutches. Doc

 

I have been thinking of doing a similar swap so this is real interesting to me.I don't know if this will work or not but if it were mine I would try using the snowmobile secondary.The primary you are using is a P-85 and the atv secondary is a P-90.They aren't cut at the right angles for a belt to work.I'm also thinking the center to center distance should be at 12.5 in. with the P-85 clutches and belt.You'll probably need lighter weights due to the atv being heavier,more friction and more rolling resistance.Hope this helps and would like to see some pics if you could.

 

I would try both snowmobile clutches since they were made to work together, then try different weights and springs as needed.

 

The stock snowmobile secondary will not mate to the jackshaft on the gearcase. Worst case, I may have to make a new jackshaft to accept the sled clutch. I may end up with the sled secondary, but it will mean cutting out my rear shock mounts and moving the engine back to get the correct spacing. I am at 10.25 now and would need 12.2

Just to see, I tried with the stock atv primary.......same result........engine revved out with slow tire speed, little to no correlation between engine RMP and tire speed.

I am going to call EPI and get the spring rate on the sled secondary and then replace my ATV spring with a spring comparable to the sleds. Hopefully that will help.
Also I had not thought to measure the clutch angles, but that may be a problem also. (thanks plumbob)

how do you post pics?

Thanks for all the help!